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Biomedical subjects

S Shoemaker

Publications and source records attributed to S Shoemaker.

14 recordsLinked to original sources
PubMed2001

Altered fibular growth patterns after tibiofibular synostosis in children.

BACKGROUND: Iatrogenic synostosis of the tibia and fibula following an operation on the leg in a child has been reported rarely in the literature, and the effects of this complication on future growth, alignment, and function are not known. This is a retrospective case series, from one institution, of crossunions of the distal parts of the tibia and fibula complicating operations on the leg in children. The purpose is to alert surgeons to this possible complication. METHODS: The senior author identified eight cases of iatrogenic tibiofibular synostosis seen in children since 1985. The patients had various diagnoses and were from the practices of four pediatric orthopaedic surgeons. Synostosis developed in six patients after osteotomies of the distal parts of the tibia and fibula, in one after internal fixation of distal tibial and fibular metaphyseal fractures through a single incision, and in one after posterior transfer of the anterior tibialis tendon through the interosseous membrane combined with peroneus brevis transfer to the calcaneus. Medical records were reviewed, and preoperative and follow-up radiographs were analyzed for changes in the relative positions of the proximal and distal tibial and fibular physes and in the alignment of the ankle. RESULTS: Five patients were symptomatic after crossunion; they presented with prominence of the proximal part of the fibula, ankle deformity, or ankle pain. Three patients were asymptomatic, and a synostosis was identified on routine follow-up radiographs. Intraoperative technical errors caused two of the crossunions; the cause of the others was unknown. Following tibiofibular synostosis, growth disturbances were noted radiographically in every patient. The normal growth pattern of distal migration of the fibula relative to the tibia was reversed, resulting in a decreased distance between the proximal physes of the tibia and fibula as well as proximal migration of the distal fibular physis relative to the distal part of the tibia. Shortening of the lateral malleolus led to greater valgus alignment of the ankle. CONCLUSIONS: Tibiofibular synostosis can complicate an operation on the leg in a child. After crossunion, the normal distal movement of the fibula relative to the tibia is disrupted, resulting in shortening of the lateral malleolus and ankle valgus as well as prominence of the fibular head at the knee. The synostosis also interferes with the normal motion that occurs between the tibia and fibula with weight-bearing, potentially leading to ankle pain.

Ankle Joint↗
PubMed2000

Founder's Award, Society for Biomaterials. Sixth World Biomaterials Congress 2000, Kamuela, HI,May 15-20, 2000. Really smart bioconjugates of smart polymers and receptor proteins.

Over the past 18 years we have been deeply involved with the synthesis and applications of stimuli-responsive polymer systems, especially polymer-biomolecule conjugates. This article summarizes our work with one of these conjugate systems, specifically polymer-protein conjugates. We include conjugates prepared by random polymer conjugation to lysine amino groups, and also those prepared by site-specific conjugation of the polymer to specific amino acid sites that are genetically engineered into the known amino acid sequence of the protein. We describe the preparation and properties of thermally sensitive random conjugates to enzymes and several affinity recognition proteins. We have also prepared site-specific conjugates to streptavidin with temperature-sensitive polymers, pH-sensitive polymers, and light-sensitive polymers. The preparation of these conjugates and their many fascinating applications are reviewed in this article.

Acrylamides↗
PubMed2000

Induction of apoptosis by conjugated linoleic acid in cultured mammary tumor cells and premalignant lesions of the rat mammary gland.

Conjugated linoleic acid (CLA) is an effective agent in preventing mammary cancer in rats treated with a carcinogen. The appearance of a tumor mass is the net result of cell proliferation minus cell death. Thus, apoptosis could be an important mechanism in controlling clonal expansion of the early premalignant lesions. The overall objective of this report was to determine whether CLA stimulated apoptosis. In the first part of the study, CLA was found to increase chromatin condensation (visualized through fluorescent 4',6-diamidino-2-phenylindole staining to DNA) and to induce DNA laddering, both evidence of apoptosis, in a rat mammary tumor cell line. The second part was to investigate the effect of CLA feeding on the development of histologically identifiable premalignant lesions in the rat mammary gland, as well as on the quantification of apoptosis (by terminal uridyltransferase nick end labeling assay) and the expression by immunohistochemistry of apoptosis regulatory proteins (bcl-2, bak, and bax) in normal versus premalignant mammary structures. CLA inhibited the formation of premalignant lesions by approximately 50%. It also significantly increased apoptosis and reduced the expression of bcl-2 in these lesions, but it did not modulate the levels of bak or bax. In contrast, neither apoptosis nor any of the apoptosis regulatory proteins was affected by CLA in normal mammary gland alveoli or terminal end buds. The data suggest that early pathological lesions may be particularly sensitive to CLA. In addition to providing a molecular basis for elucidating the mechanism of action of CLA in cancer prevention, the research on CLA-responsive biomarkers also has a practical side because these assays can be applied to biopsied human tissue samples in future CLA intervention trials.

Animals↗
PubMed1999

Adipocyte-epithelial interactions regulate the in vitro development of normal mammary epithelial cells.

Mammary epithelial organoids (MEO), isolated from pubescent rats, were cultured within a reconstituted basement membrane in transwell inserts, in the presence or absence of mature mammary adipocytes in the lower well. This system allowed for free medium exchange between the two compartments, without direct cell-to-cell contact. When cultured in serum-free medium supplemented with insulin, prolactin, hydrocortisone, progesterone, and various epidermal growth factor (EGF) concentrations, mammary adipocytes did not affect epithelial cell growth, but enhanced epithelial differentiation. Casein and lipid accumulations were monitored as indicators of functional differentiation of MEO. Mammary adipocytes significantly enhanced casein and lipid accumulation within the MEO, independently of EGF concentration. Furthermore, adipocytes induced MEO to preferentially undergo alveolar morphogenesis, inhibited squamous outgrowth, and increased lumen size. These findings demonstrate that morphological and functional differentiation of mammary epithelial cells is profoundly enhanced by the adipose stroma and that these effects are mediated by diffusible paracrine factors. This new model can be exploited in future studies to define the mechanisms whereby hormones and growth factors regulate mammary gland development and carcinogenesis. Moreover, it could complement in vivo reconstitution/transplantation studies, which are currently employed to evaluate the role of specific gene deletions in the regulation of mammary development.

Adipocytes↗
PubMed1998

A model for enhancing worldwide personal health and wellness.

Individuals must increasingly take control of managing their own health affairs. This requires access to quality information that is not easily obtained from traditional social institutions. NetWellness is an electronic consumer health information service that provides a model for reaching the goal of enhancing personal health and quality of life. [1] We present a vision of consumer health information delivery in the 21st century, and a model for reaching that vision. Our experience to date, progressing through a five-phase model, is aimed at providing the best health information possible to the widest population possible.

Community Participation↗
PubMed1996

An electronic consumer health library: NetWellness.

NetWellness is a community-based, consumer-defined grant program supporting the delivery of electronic health information to rural residents of southern Ohio and urban and suburban communities in the Greater Cincinnati tri-state region. NetWellness is a collaboratively developed and publicly and privately funded demonstration project. Information is delivered via ISDN, standard dial, dedicated network connections, and the Internet. TriState Online (Greater Cincinnati's Free-Net) and other southern Ohio Free-Nets are key access points in the larger project communities. The other access points are more than forty workstations distributed at public sites throughout the project's primary geographical area. Design strengths and limitations, training initiatives, technical issues, and the project's impact on medical librarianship are examined in this paper. Also discussed are ways of determining community needs and interest, building political alliances, finding and developing funding sources, and overcoming technical obstacles. NetWellness's Internet address is: http:@www.netwellness.org.

Community Participation↗
PubMed1995

XX male pseudohermaphroditism in a horse.

A pseudohermaphrodite horse with aggressive stallion-like behavior and ambiguous external genitalia was gonadectomized. The hypoplastic gonads removed from the abdomen were confirmed by histologic examination to be testes. Examination of blood and fibroblasts revealed a 64,XX karyotype.

Animals↗
PubMed1995

In vitro characterization of the human recombinant soluble granulocyte-macrophage colony-stimulating factor receptor.

We have cloned, expressed, and partially purified a naturally occurring, truncated, soluble form of the human granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor alpha subunit to investigate its biochemical and biologic properties. The soluble receptor species lacks the transmembrane and cytoplasmic domains that are presumably removed from the intact receptor cDNA by a mechanism of alternative splicing. The resulting soluble 55- to 60-kD glycosylated receptor species binds GM-CSF with a dissociation constant (kd) of 3.8 nmol/L. The soluble GM-CSF receptor successfully competes for GM-CSF binding not only with the transmembrane-anchored GM-CSF receptor alpha subunit but also with the native oligomeric high-affinity receptor complex. In addition, in human bone marrow colony-forming assays, the soluble GM-CSF receptor species can antagonize the activity of GM-CSF. Our data suggest that the soluble GM-CSF receptor may be capable of acting in vivo as a modulator of the biologic activity of GM-CSF.

Binding, Competitive↗
PubMed1993

Functionalism and consciousness.

It is widely held that a mental state and the subject's introspective belief about it are always 'distinct existences' and only contingently connected. This suggests that for each sort of mental state there could be a creature that is introspectively 'blind' with respect to states of that sort, meaning that while it is capable of having such states, and of conceiving of itself as having them, it is totally without introspective access to its states of that sort. It is argued here that introspective blindness with respect to many sorts of mental states, in particular beliefs and sensory states, is not a possibility, because it is incompatible with requirements of rationality that are internal to the functional roles that are constitutive of these states. Introspective accessibility is essential to the functional roles of such mental states when the conceptual and cognitive resources of the subject of those states are sufficiently rich to make beliefs and thoughts about them a possibility. This is a version of the view that such states are necessarily self-intimating and is incompatible with the perceptual model of introspection favoured by some functionalists as well as by many non-functionalists.

Awareness↗
PubMed1992

A human recombinant haemoglobin designed for use as a blood substitute.

The need to develop a blood substitute is now urgent because of the increasing concern over blood-transmitted viral and bacterial pathogens. Cell-free haemoglobin solutions and human haemoglobin synthesized in Escherichia coli and Saccharomyces cerevisiae have been investigated as potential oxygen-carrying substitutes for red blood cells. But these haemoglobins cannot be used as a blood substitute because (1) the oxygen affinity in the absence of 2,3-bisphosphoglycerate is too high to allow unloading of enough oxygen in the tissues, and (2) they dissociate into alpha beta dimers that are cleared rapidly by renal filtration, which can result in long-term kidney damage. We have produced a human haemoglobin using an expression vector containing one gene encoding a mutant beta-globin with decreased oxygen affinity and one duplicated, tandemly fused alpha-globin gene. Fusion of the two alpha-globin subunits increases the half-life of this haemoglobin molecule in vivo by preventing its dissociation into alpha beta dimers and therefore also eliminates renal toxicity.

Animals↗
PubMed1990

Direct detection of Mycobacterium tuberculosis in clinical specimens by DNA amplification.

A polymerase chain reaction assay was developed for the amplification of a 336-bp repetitive fragment in the chromosome of Mycobacterium tuberculosis. The assay is specific for M. tuberculosis and can be used to detect the amount of DNA present in less than 10 organisms. It was used to demonstrate M. tuberculosis DNA in 14 of 26 clinical specimens (from cerebrospinal fluids, pleural fluid aspirates and biopsies, pericardial fluid aspirates, and an open lung biopsy), and it was shown to be at least as sensitive as conventional culture techniques with these specimens.

Base Sequence↗
PubMedDate not supplied

Approaching equity in consumer health information delivery: NetWellness.

The growing public interest in health and wellness information stems from many sources, including social changes related to consumers' rights and women's health movements, and economic changes brought about by the managed health care revolution. Public, hospital, and medical center libraries have been ill-equipped to meet the increasing need for consumer-oriented materials, even though a few notable programs have been established. The "Information Superhighway" could be an effective tool for sharing health information if access to telecomputing equipment and training were available to those with an information need. The University of Cincinnati Medical Center, with its libraries in the leading role, is delivering NetWellness, an electronic consumer health library service, to residents of 29 counties in three midwestern states. Users connect directly through the Internet, through regional Free-Nets, and by visiting one of 43 public access sites where networked workstations have been installed. The continued success of the project depends on developing partnerships, providing quality content and maintaining fair access.

Community-Institutional Relations↗
PubMedDate not supplied

The morphology of abdominal and inguinal cryptorchid testes in stallions: a light and electron microscopic study.

Eleven unilateral cryptorchid stallions, two to three years old, were castrated at Louisiana State University Veterinary Teaching Hospital. Five of these cryptorchid cases were abdominal and the rest were inguinal. This study was initiated to document the differences between the abdominal and inguinal equine cryptorchid testes. Specimens were obtained from the abepididymal side of each cryptorchid testes and processed for light and electron microscopic study. The cryptorchid testes were smaller than the scrotal testes, with the abdominal testes being one-fourth the size of the scrotal testes. Two of the abdominal testes had cysts filled with a straw-colored fluid. The seminiferous tubules of the abdominal testes were larger than those in the inguinal testes. The epithelial linings of the seminiferous tubules of the abdominal testes were vacuolated and did not contain more than two layers of undifferentiated cells. The interstitial collagen fibers of the abdominal testes were coarse and more abundant than those of the inguinal testes. The seminiferous tubules of the inguinal testes were smaller and contained many layers of epithelial cells at different stages of embryological differentiation, with scattered primordial germ cells. The necrotic, degenerative changes of the epithelial cells of the abdominal testes were distinct, while the inguinal testes had healthy cells at embryological arrest.

Animals↗